Considering the complexities and particularities of each district heating (DH), RELaTED concept has been implemented in four different DH networks covering extremely different climatic conditions, construction traditions, urban density, pre-existing district scheme, ownership and energy services contract schemes:

Large district heating in operation in Belgrade, Serbia

The district heating network of Belgrade comprises 750km and delivers 3500GWh to approximately 50% of the city.

Belgrade is the capital and largest city of Serbia. Its urban area has a population of 1.34 million, while over 1.65 million people live within its administrative limits.

The city of Belgrade is served by the district heating operated by Beoelektrane. This network comprises 750km and delivers 3500GWh to approximately 50% of the city.

Within RELaTED, Beoelek has deployed the following conversion activities to the district heating network in Belgrade:

  • Low temperature conversion of one subnetwork comprising several households and apartment buildings with modern insulation levels. Network temperature levels of ~50-55ºC have been reached in this conversion.
  • Connection of large solar heat production plant.
  • Planning, tendering and construction of a cogeneration plant of 10MW of electric power plant with an estimated heat output of 64,000MWt/year.
  • Promotion of adoption of new technologies developed by customers and partners connected to the Belgrade DH network.

Demonstration activities in Denmark

Regarding Denmark, it was proposed to showcase the ULT DH concept in a new urban development in Vinge, where 36 interconnected townhouses (with mandatory connection), and 23 detached houses (with voluntary connection) were to be built.

Due to external reasons to the RELaTED consortium, the demonstration capacity of VINGE was largely reduced in relation to integration of project technologies in buildings.

Alternative detached house in DTI (ENERGYFLEXHOUSE) were used as equivalent location. In the ENERGY FLEX HOUSES, 3FS, DHRHP, BILTST and DHW boosters were tested under realistic boundary conditions, connected to the DH network serving the 2 houses (1 is inhabited).

Flexibility schemes in relation to price signals and DH flow temperature levels were also studied. The outcomes showed the feasibility of these technologies.

DH in operation with large share of biomass in Tartu, Estonia

With over 90.000 inhabitants, Tartu is the second largest city of Estonia. Tartu is served by a district heating system privately owned and operated by GREN. Yearly 500GWh are delivered to over 1500 consumers in the city, 94% of this energy is obtained from biomass and peat.

Main consumers are collective housing (49%), industry and commercial buildings (33%) and individual housing (18%), with 40-60 new connections to the grid per year.

94% of the energy delivered to Tartu consumers is obtained from biomass and peat.

Within RELaTED, GREN has develop the following implementations:

  • ULT conversion of the TARKON-TUGLASE DH network area comprising 54 consumers totalling 4.3MW with a network length of 4.6 km. Technical limitations of the DH network have been investigated, and associated feasible technical and economically viable conversion scenarios identified. The reduction of temperature achieved thermal savings in the range of 400MWh/year.
  •  Connection of excess heat from cooling applications to the DH network, with a total injection of 2.5 GWh on the first year of operation.
  • Connection of excess heat from cooling applications to the DH network.
  •  A replication project was also executed with the objective of recovering heat from the closed cooling system of a CHP plant, with an estimated potential of 1.3MW of heat recovery and 10 GWh/year of heat produced.

Corporate DH with mixed uses in Iurreta, Basque Country, Spain

Iurreta heat production system delivers space heating and domestic hot water to a set of building owned by the Basque Government.

Iurreta is located in the northern coast of Spain. The demonstration site consists on a set of buildings owned by the Basque Government. The building complex hosts part of the emergency, rescue and fast intervention groups of the Ertzaintza (regional police of the Basque Country).

The campus is composed by a total of 14 multi-rise buildings with different characteristics and uses.  Heat needs in the complex are covered by means of a centralized heat production system with an installed total power of 650 kW, operative at 80/60ºC, which delivers space heating and domestic hot water.

In addition to centralized system, several independent heat pumps are used to serve a small subset of small buildings. Several buildings in the campus are equipped with cooling systems comprising chillers connected to fan-coil systems.

Within RELaTED, the following activities have been performed:

  • ULT conversion of the DH network, with LT conversion of heat delivery systems within buildings. Operation temperatures in the main distribution network have been adapted for at~40-45ºC. Distribution systems at buildings requiring higher distribution temperature have been fed by means of DHRHP to allow service temperatures in the range of ~50-55ºC.
  • Integration of BILTST system in South exposed walls.
  • Integration of DHRHPs in buildings equipped with cooling plants.
  • Densification of the DH network with the connection of presently isolated HVAC plants.
  • Adaptation of control strategies to ensure maximum use of BILST and Heat pump capacity.

Feasibility studies

Within RELaTED, feasibility studies have been performed for the development of new district heating networks in already consolidated urban environments. These studies have been conducted at regional scale, where regional energy agencies of the Basque Country (EVE) and Mazovia Energy Agency have identified:

  • industrial waste heat sources suitable of heat recovery,
  • possible renewable resources such as solar thermal,
  • and geothermal heat production capacity.

Considering this de-carbonized heat generation capacity, these studies have identified candidate urban areas of ULT DH systems. Also, the studies have incorporated technical and financial information about:

  • the cost of setting up heat delivery infrastructure,
  • capacity and cost estimation of additional backup heat sources,
  • development phases of the DH network, etc.

Additionally, an administrative roadmap has been developed to incorporate requirements related to the modification of energy, regional and urban planning documents to allow and support the installation of such an infrastructure.